Cluster down when kill indexer process

Our couchbase cluster went down when we were killing index creation command. Cluster could not come up after that. On hard restart of each node (we are fine with loosing some of the data), we see following erros in the logs we see following error:
Namespace default - cause: HTTP error 500 Internal Server Error getting “”: [“Unexpected server error, request logged.”]
[goport] 2017/04/17 09:33:19 /opt/couchbase/bin/cbq-engine terminated: exit status 1

@shiv.kalasgonda, how did you try to kill the index creation command?

Can you provide more details about your cluster setup in terms of how many nodes and what services you are running on each node. After restart of nodes, are all services down or some of them?